The present disclosure relates to an imaging apparatus and more particularly, to an imaging apparatus that performs correction of shading generated by an operation of a shutter, on the basis of an elliptical shape inclined in a direction according to an operation direction of blade members, and improves image quality.
In various imaging apparatuses such as a video camera and a still camera, a shutter is operated at the time of photographing and an image is generated. In addition, the shutter is operated by opening/closing of blade members.
In such an imaging apparatus, because the blade members are opened and closed at the time of photographing, an amount of light (exposure amount) to be taken by each region of an image becomes different. That is, in a closing operation of the blade members, an outer circumferential portion of the image is closed immediately after movement of the blade members starts and a center portion of the image is closed after the outer circumferential portion is closed. In an opening operation of the blade members, the center portion of the image is opened immediately after the movement of the blade members starts and the outer circumferential portion of the image is opened after the center portion is opened. Therefore, a time for which the image is closed by the blade members increases as the region of the image comes close to the outer circumferential portion from the center portion. For this reason, an amount of light taken in the outer circumferential portion of the image becomes smaller than an amount of light taken in the center portion of the image. As a result, irregularities of the amounts of light are caused by the regions of the image and shading is generated.
Therefore, in the imaging apparatus, correction of the shading is performed to prevent image quality from being deteriorated due to the shading, that is, remove a difference in light and dark by the regions of the image.
As a method of correcting the shading, a method of correcting the shading on the basis of an elliptical shape inclined to an image has been known (for example, Japanese Patent Application Laid-Open (JP-A) No. 2004-38728).